In the field of ultrasonic diagnostics, acoustic images of anatomical structures are utilized in the diagnosis of various disorders. In order to produce real-time images of the anatomical structures, beams of ultrasonic energy from a probe are transmitted into the body tissue of a patient and echoes received by the ultrasonic probe are rapidly processed into an image format suitable for display. It is desirable that the probe produce an image over a wide field of view using a sector scan format. A sector scan format generates an image by repeatedly transmitting and receiving ultrasonic energy in radial directions away from the probe to define a fan-like pattern. The ultrasonic beam is directed by mechanically moving an ultrasonic transducer such that it is swept through an arc about a pivot axis to produce the fan-like sector scan pattern.
The prior art is replete with examples of ultrasonic transducer probe assemblies, such as those disclosed in U.S. Pat. No. 4,149,419 entitled "Ultrasonic Transducer Probe" issued Apr. 17, 1979 to R. Connell et al.; U.S. Pat No. 3,955,561 entitled "Cardioscan Probe" issued May 17, 1976 to R. Eggleton; U.S. Pat. No. 4,421,118 entitled "Ultrasonic Transducer" issued Dec. 20, 1983 to J. Dow et al.; U.S. Pat No. 4,479,388 entitled "Ultrasonic Transducer and Drive System" issued on Oct. 30, 1984 to T. Matzuk; U.S. Pat. No. 4,399,703 entitled "Ultrasonic Transducer and Integral Drive Circuit Therefor" issued on Aug. 23, 1983 to T. Matzuk; U.S. Pat No. 4,092,867 entitled "Ultrasonic Scanning Apparatus" issued on Jun. 6, 1978 to T. Matzuk; U.S. Pat. No. 4,246,792 entitled "Self-Contained Ultrasonic Scanner" issued Jan. 27, 1981 to T. Matzuk; U.S. Pat. No. 4,398,425 entitled "Ultrasonic Scanning Transducer" issued on Aug. 16, 1983 to T. Matzuk; U.S. Pat No. 4,841,979 entitled "Ultrasonic Prostate Probe Assembly" issued on Jun. 27, 1989 to Dow et al.; and U.S. Pat. No. 4,913,155 entitled "Ultrasonic Transducer Probe Assembly") issued On Apr. 3, 1990 to Dow et al.
Although all of the above-referenced patent disclosures address various problems associated with the use of ultrasonic transducer imaging, none have addressed the particular problems associated with the ultrasonic imaging of internal organs by positioning the ultrasonic probe within the body in close proximity to the organ to be imaged. More particularly, none of the cited patent disclosures address the problem of feeding an ultrasonic probe through narrow anatomical passageways such as the urethra, cervix, fallopian tubes, and major vessels of the vascular system, and the like.
Contemporary ultrasonic probe assemblies thus must image such internal anatomical structures through or around various obstructing anatomical structures, i.e. bones, blood vessels, and various organs. As such, the ability to image desired internal organs is often limited. The field of view may be severely restricted and/or the resolution reduced. Thus, it would be desirable to place an ultrasonic probe in close proximity to the organ being imaged even when that organ is disposed deep within surrounding tissue.
It is well known to provide visual images of internal organs by utilizing endoscopes. Various different types of endoscopes are known for viewing various anatomical structures. For example, upper endoscopes are utilized in the examination of the esophagus, stomach, and duodenum; colonoscopes are utilized for examining the colon, angioscopes are utilized for examining blood vessels, and arthroscopes are utilized for examining the various joint spaces. However, all such endoscopes are limited to providing visual images of the exterior surfaces or accessible portions of the desired anatomical structures. One cannot probe or see into the interior of organs when utilizing an endoscope without first disposing the endoscope within the organ. Thus, an invasive surgical procedure is necessary to utilize an endoscope in the viewing of such organs.
As such, although the prior art has recognized to a limited extent the problem of ultrasonically imaging internal or obstructed portions of the human anatomy, the proposed solutions have to date been ineffective in providing a satisfactory remedy.